1. Field of the Invention
The present invention relates to flotation devices for allowing a person to walk on water, more specifically, to an improved lightweight, inflatable, self-propelled pair of water walkers for water transportation and personal recreation.
2. Description of the Prior Art
The earliest historical reference to water walkers is found in the writings of Merejkowski, who, surveying Leonardo Da Vinci's workshop by moonlight, discovers "pointed boat-shaped skiis for walking over water." Since that time, there has been a continuing interest in developing devices that better enable people to walk on water.
Since issue of the first water walker patent, U.S. Pat. No. 22,457, Dec. 28, 1858, of Rowlands, there have been numerous attempts to solve the inherent problems associated with walking on water. For example, the Rowlands patent reveals a common solution to the spread eagle dilemma (i.e. the tendency to have the pontoons float apart in the water which can cause the user to lose balance) with pivoting tie bars fore and aft which keep the two bouyant pontoons parallel. However, this solution limits freedom of motion and makes turning difficult.
Another poblem concerns the placement of the user's feet with respect to the pontoon's center of bouyancy. U.S. Pat. No. 3,777,324, Dec. 11, 1973, of Jenkins sought to solve this problem by securing the feet on top of the pontoon. However, this arrangement creates instability by placing the user's weight above the pontoon's center of bouyancy. Counteracting instability requires a large keel, such as shown in U.S. Pat. No. 2,651,790, Sep. 15, 1953, of Geiger. However, this feature adds weight and draft to the device.
Another issue with these devices is hydrodynamic design, where form and texture allow smooth and efficient movement over the water. Meyer, U.S. Pat. No. 1,463,330, Jul. 31, 1923, shows an inflatable device which folds accordion-like into a compact package. However, the accordion-like folds result in a high coefficient of drag, making movement over water sluggish.
Other designs simply did not appear workable. For example, U.S. Pat. No. 3,134,114, May 26, 1964, of Stimm, and U.S. Pat. No. 3,750,203, Aug. 7, 1973, of Ceccato, illustrate devices whose width is significant enough to create tremendous stability. However, this width also forces the user to stride with legs wide apart. This causes fatigue and thereby limits the distance one can travel on them.
Quick and easy withdrawal of the foot from a water walker or water ski is also essential for safe use. Some designs clearly failed in this area. Nayes, in U.S. Pat. No. 5,080,621, Jan. 14, 1992, utilizes threaded fasteners to secure a user's shoe to the water walking device. In the event of a fall, the user would have to work underwater holding his or her breath while trying to unscrew two thumbscrews and a wingnut. This could easily turn into a life-threatening situation.
Other means are also helpful in propelling the water skiis across the water. For example, in U.S. Pat. No. 2,577,917, Dec. 11, 1951, Root employs a sail which requires holding with both hands; however, no provisions are described for folding or storing it, should wind conditions negate its use.
Fines, in U.S. Pat. No. 3,027,576, Apr. 3, 1962, discloses a propulsion cup at the bottom of a ski pole. However, he fails to define a means to prevent cup inversion.
Another significant consideration in the commercialization of a water walker product is simplicity. However, the complexity and large number of parts found in U.S. Pat. No. 4,846,743, Jul. 11, 1989, of Ping-chuan make it expensive to manufacture.
Moreover, virtually all of the prior art result in designs that are too bulky, too heavy, or too complex to permit transport in a backpack.
Thus, there is a need in the art to provide an easy to use, stable, compact, and simple water walker design that overcomes all of the aforementioned disadvantages and results in an innovative, safe and versatile recreational and water transportation system.